MD Extensions: Show messages for no extensions, and for no search results

chrome/browser/resources/md_extensions/item_list.js

Index: chrome/browser/resources/md_extensions/item_list.js
diff --git a/chrome/browser/resources/md_extensions/item_list.js b/chrome/browser/resources/md_extensions/item_list.js
index 109feeb337010a5799fe1b28548e582c9e6fbe60..8794ab286cd41247049166d236a9c1a3d5546fbd 100644
--- a/chrome/browser/resources/md_extensions/item_list.js
+++ b/chrome/browser/resources/md_extensions/item_list.js
@@ -21,6 +21,12 @@ cr.define('extensions', function() {
       },
 
       filter: String,
+
+      /** @private */

[dpapad, 2017/07/07 00:45:04]

Can we annotate what does the array hold? !Array<SomeTypedef>

[scottchen, 2017/07/07 23:08:42]

Done.

+      shownItems_: {
+        type: Array,
+        computed: 'computeShownItems_(items.*, filter)',
+      }
     },
 
     listeners: {
@@ -73,6 +79,10 @@ cr.define('extensions', function() {
         return item.name.toLowerCase().includes(this.filter.toLowerCase());
       }, this);
     },
+
+    isEmpty_: function(length) {
+      return length == 0;
+    }
   });
 
   return {